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Differentiated thermal crystallization from amorphous chenodeoxycholic acid between the ground specimens derived from
Toshio Oguchi1, Nahomi Sasaki, Tetuya Hara
1Graduate School of Pharmaceutical Sciences, Chiba University, 1-33 Yayoicho, Inage-ku, Chiba 263-8522, Japan.
International Journal of Pharmaceutics
|February 21, 2003
Summary
Amorphous chenodeoxycholic acid (CDCA) crystallization is influenced by its physical state. Crystal nuclei from different forms significantly impact the amorphous CDCA crystallization process and temperature.
Area of Science:
- Solid-state chemistry
- Materials science
- Crystallization studies
Background:
- Chenodeoxycholic acid (CDCA) exists in multiple polymorphic forms.
- Amorphous forms can exhibit different crystallization behaviors compared to crystalline precursors.
- Understanding amorphous material crystallization is crucial for pharmaceutical and materials applications.
Purpose of the Study:
- To investigate the crystallization behavior of amorphous chenodeoxycholic acid (CDCA).
- To determine the influence of different crystalline forms (form I and form III) on the amorphous state.
- To elucidate the role of crystal nuclei in the crystallization process.
Main Methods:
- X-ray diffraction (XRD) for structural analysis.
- Infrared (IR) spectroscopy for chemical state assessment.
- Differential scanning calorimetry (DSC) for thermal analysis and crystallization monitoring.
Main Results:
- Grinding of CDCA form I and form III resulted in amorphous states indicated by XRD halos.
- Amorphous samples derived from form I and form III crystallized to form I at 120°C and 147°C, respectively.
- Mixing ground form III with ground form I lowered crystallization temperature, dependent on form I content.
- Co-ground samples exhibited dual crystallization modes for form I.
Conclusions:
- The physicochemical state of ground CDCA samples differs significantly.
- Crystal nuclei act as critical factors influencing the crystallization pathway of amorphous CDCA.
- The presence and type of crystal nuclei dictate the crystallization temperature and kinetics.